This is one way to switch to a root prompt. This will ask for your users password and then give you a root prompt.
homer@deep-thought ~ $ sudo -i [sudo] password for homer: deep-thought ~ # |
This is another method using the sudo command to run the su utility.
homer@deep-thought ~ $ sudo su - [sudo] password for homer: deep-thought ~ # |
Adding your user to the sudoers group is essential to be able to run the sudo command and gain elevated privileges. Use the command below to check if your user is a member of the sudoers group.
deep-thought ~ # cat /etc/group | grep sudo sudo:x:27:homer |
This is what my sudoers file looks like; you edit this file with the sudo visudo command. Otherwise you could make an error when editing the file and lock yourself out of the system.
deep-thought ~ # cat /etc/sudoers # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults env_reset Defaults mail_badpass Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" # Host alias specification # User alias specification # Cmnd alias specification # User privilege specification root ALL=(ALL:ALL) ALL # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL # Allow members of group sudo to execute any command %sudo ALL=(ALL:ALL) ALL # See sudoers(5) for more information on "#include" directives: #includedir /etc/sudoers.d |
This is the output after loading the sudoers file and then exiting without saving changes. The file is loaded as a temporary file, this is scanned before saving to make sure that the file contains no errors.
deep-thought ~ # visudo visudo: /etc/sudoers.tmp unchanged |
The su -c command may also be used to run a single command as root.
homer@deep-thought ~ $ su -c '/sbin/ifconfig' Password: su: Authentication failure |
But this did not work due to the fact that Linux Mint 15 does not have the root account enabled. To accomplish this, type this command.
homer@deep-thought ~ $ sudo passwd root [sudo] password for homer: Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully |
Then the command may be completed successfully.
homer@deep-thought ~ $ su -c '/sbin/ifconfig' Password: eth0 Link encap:Ethernet HWaddr 6c:f0:49:b5:e6:2a UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr 00:13:46:3a:02:83 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:1334 errors:0 dropped:0 overruns:0 frame:0 TX packets:1334 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:180793 (180.7 KB) TX bytes:180793 (180.7 KB) wlan0 Link encap:Ethernet HWaddr e0:91:f5:23:fd:ad inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::e291:f5ff:fe23:fdad/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:80342 errors:0 dropped:0 overruns:0 frame:0 TX packets:59933 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:96793242 (96.7 MB) TX bytes:8551564 (8.5 MB) |
If you wish to lock a root account and only use the sudo command, type this at a prompt.
homer@deep-thought ~ $ sudo passwd -l root passwd: password expiry information changed. |
Then if you try and login, you will get an error.
homer@deep-thought ~ $ su Password: su: Authentication failure homer@deep-thought ~ $ |
This is how easy it is to work with user accounts on Linux and UNIX. The sudo command is very powerful, but if you are on a shared computer system always close the terminal window after using the sudo command. The sudo privileges are remembered for 15 minutes so this gives added security if you close the terminal session properly. Use Ctrl-D or type exit to close the session.